Many Sunnis accuse the military of siding with their rivals, the powerful Shi’ite group Hezbollah, as sectarian tensions grow in Lebanon, stoked by the civil war in neighboring Syria. Since December, four attacks have killed five soldiers, with warnings of more to come.

The tensions add another trigger for potential conflict within Lebanon.

The sectarian divide is growing increasingly explosive, with Sunnis largely backing their brethren in Syria, while Shi’ites and Hezbollah support the government of Syrian President Bashar Assad.

That violence has ricocheted into Lebanon, with Sunni militants carrying out more than a dozen bombings against Shi’ite areas since July, killing dozens and terrifying the country.

As Lebanon’s military moves against the militants, they risk fueling further anger among the wider Sunni community — not because there is much sympathy for extremists, but from the perception the army is punishing Sunnis for backing rebels while allowing Hezbollah to help Assad.

‘‘The army doesn’t act fairly. They crush Sunnis with their feet,’’ said grocer Umm Zaher, 56, in a Sunni neighborhood of the Lebanese capital Beirut. She and most Sunnis interviewed declined to give their full names, fearing retaliation from the army or Hezbollah.

‘The army doesn’t act fairly. They crush Sunnis with their feet.’

Umm Zaher, a grocer in a Sunni neighborhood of Beirut

‘‘The army is theirs,’’ said taxi driver Khaled, 32, referring to Hezbollah.

Blue flags fluttered from nearby street lights, the symbol of a Sunni-dominated political bloc once led by assassinated Sunni Prime Minister Rafik Hariri. ‘‘It’s everywhere in Sunni areas that people feel this way,’’ said Sunni cleric Raed Hlayhel of Tripoli.

Criticizing the army was once rare. The institution is widely seen as a unifying force, drawing recruits across Lebanon’s patchwork of Christian and Muslim sects.

The army is an important economic vehicle for Sunni advancement and composes at least one-third of its forces, said Aram Nerguizian, an expert on Lebanon’s military at the Center for Strategic and International Studies in Washington.

Nevertheless, that and the offer of $3 billion to the army from Saudi Arabia, an ally of Lebanese Sunnis, has not shaken the perception among Sunnis that the army is against them. Lebanese army officials did not respond to requests for comment.

Sunnis have long resented Hezbollah’s dominance of Lebanon’s politics and the untouchable, state-within-a-state status it enjoys. Its guerrilla force also is stronger than the military.

Sunnis began souring toward the army in May 2008, when Hezbollah-loyal gunmen rampaged through Sunni areas of Beirut, after years of political disputes, and soldiers did nothing to stop them.

Sunnis now accuse Lebanon’s army of targeting their brethren funneling weapons, helping and harboring Syrian rebels, while ignoring Hezbollah’s actions.

‘‘When the law is only applied to one side, it creates grievances,’’ Sunni politician Mustafa Alloush said. ‘‘What the Sunni street feels is that there’s winking toward Hezbollah, and severity toward the other side.’’